Cold, lack of snow concern wheat industry

Washington wheat farmers are waiting to see how much damage the winter weather is causing on their crop. Lower temperatures without snow cover in February and March could coincide with the plants' beginning to lose their tolerance to come out of dormancy, says Washington State University wheat breeder Arron Carter.

If the weather stays warm, they will probably recover, Carter said, but another cold snap would likely cause some damage.

Glen Squires, CEO of the Washington Grain Commission, said the lack of snow cover might mean more winterkill this year compared to last year, but the extent of the damage won’t be clear until March. Potential impacts will vary by location, Squires said.

“We anticipate some areas will have some damage,” he said.

Temperatures have been below normal, said Nic Loyd, meteorologist with WSU’s AgWeatherNet in Prosser, Wash. A 10-12 day arctic period in December brought temperatures in the 13-20 degrees Fahrenheit range during the day and as low as zero at night. The rest of the winter has been a little warmer, Loyd said, but drier conditions have contributed to farmer concerns.

Plants enter winter dormancy with a high level of cold tolerance, which degrades over the season, Carter said. The plants acclimate as the temperature gets lower, but their tolerance peaks in November or December. By February and March, the plants begin to lose the cold tolerance as they come out of dormancy.

The worst damage tends to occur during cold weather in February and March without snow cover, Carter said.

Some farmers are taking the precaution of ordering spring wheat to replace affected winter wheat in some areas, Carter said. The spring wheat seed supply could be pretty “snug,” Squires said.

Carter and other breeders are looking for ways to boost cold tolerance in wheat.

USDA Agricultural Research Service wheat genetics research leader Dan Skinner studies the response of wheat plants as the temperature drops below freezing in Pullman, Wash.

Skinner found that survival doubles after exposing the wheat to about 26 degrees Fahrenheit for 24 hours and warming conditions to 37 degrees for another 24 hours. The survival rate doubles again when repeated.

Roughly 26 degrees Fahrenheit is when ice crystals begin to form in the wheat cells. Skinner thinks the crystals change the plant’s physiology, and the plant responds.

If researchers understand how the system works, Skinner said, they can improve or develop wheat varieties with better cold tolerance.

Skinner watches the wheat plant’s physiological response to freeze-thaw cycles. If he can determine that lipids — fatty acids — are involved, that should be a relatively simple thing to breed for, he said. Lipid formation is fairly well understood by plant physiologists, he said.

“The chances of getting plants that can withstand long-term freezes are probably pretty good,” he said.

Skinner believes the work will be folded into ongoing variety development in the next few years and beyond.

“The seasons we’ve experienced in the last few years are different from what (farmers) experienced 10 or 20 years ago,” he said. “This whole concept of dealing with weather-related responses, we’re dealing with a moving target. That’s something we just have to acknowledge and deal with.”